you should be more specific when posting your questions:
used versions of openldap, cyrus sasl and kerberos (at last: mit / heimdal?)

openldap: 2.3.27
cyrus sasl: 2.1.22 (binary package and sources)
kerberos: k5 heimdal
mod_auth_kerb: 5.1.3
krb5-server: 1.6.1-17 (on kerberos-server, runs on a different server)
without any information about your config-files and posting of
a log-output with a high debug-level, it is quite difficult to answer
this at all.